FirebaseDatabase Framework Reference

FIRDataSnapshot

@interfaceFIRDataSnapshot:NSObject

A FIRDataSnapshot contains data from a Firebase Database location. Any time you read
Firebase data, you receive the data as a FIRDataSnapshot.

FIRDataSnapshots are passed to the blocks you attach with observeEventType:withBlock: or observeSingleEvent:withBlock:.
They are efficiently-generated immutable copies of the data at a Firebase Database location.
They can’t be modified and will never change. To modify data at a location,
use a FIRDatabaseReference (e.g. with setValue:).

Gets a FIRDataSnapshot for the location at the specified relative path.
The relative path can either be a simple child key (e.g. ‘fred’)
or a deeper slash-separated path (e.g. ‘fred/name/first’). If the child
location has no data, an empty FIRDataSnapshot is returned.